Valve-gear.



(-No Hidden.)

Patented Nov. 26, l90l.

J. A. PIERCE.

VALVE GEAR.

(Application filed Apr. 6, 1901.)

2 Sheets-Sheet l.

No. 687,402. Patented'Nov. 26, IBM.

J. A. PI'ERCE.

VALVE GEAR.

[Application filed Apr. 6, 1901.)

(No Model.) ZShaets-Sheet 2.

w guveufo'n UNITED STATES q PATENT @nnrcn.

JOHN A. PIERCE, OF ASHGROVE, MISSOURI.

VALVE-G EAR.

SPECIFICATION forming part of Letters Patent No. 687,402, dated November 26, 1901. Application filed April 6, 1901. Serial No.54,6'79. (No modeld T at whom it may concern:

Be it known that I, J OHN A. PIERCE, a citizen of the United States, residing at Ashgrove, in the county of Greene and State of Missouri, have invented certain new and useful Improvements in Valve-Gear; and I do hereby declare the following to bea full, clear, and exact description of the invention, such as Will enable others skilled in the art to which it appertains to make and use the same.

This invention has relation to valve-gear for operating and reversing the motion of the valve of steam and kindred engines actuated by a motive medium alternatelyadmitted into a cylinder upon opposite sides of a piston working therein.

Thisinvention materially simplifies, cheapens, and reduces the cost of maintenance of reversing valve-gear for engines and enables all the parts to be readily reached for making repairs, cleaning, oiling, and the like.

For a. full description of the invention and the merits thereof and alsoto acquire a knowledge of the details of construction of the means for efiecting the result reference is to be had to the following description and drawings hereto attached.

While the essential and characteristic features of the invention are necessarily susceptible of modification, still the preferred embodiment of the invention is illustrated in the accompanying drawings, in which- Figure 1 is a side elevation showing the application of the invention. Fig. 2 is a perspective view of the valve-gear. Fig. 3 is a top plan View. Fig. 4 is a detail view in perspective of a slide or box.

Corresponding and like parts are referred to in the following description and indicated in all the views of the drawings by the same reference characters.

The valve-gear is adapted for an engine of any type comprising a piston working in a cylinder and a slide-valve for controlling the admission of steam'or other motive medium into the said cylinder in alternation upon opposite sides of the piston.

In the drawings the bed or frame of the engine is indicated at 1, the guide for the cross-head at 2, the pitman for connecting the cross-head with the crank-shaft at 3, and the cross-head at 4.. The reversing-bar 5 is connected with the reversing lever 6 by means of rods 7 and 8 and the pivoted arm 9, the inner ends of the rods 7 and 8 having pivotal connection with the arm 9 atdifierent distances from the axis orpivotalcenter thereof. While the reversing-bar 5 may be mounted in any desired way so long as its relative inclination may be changed according as it may be required to drive the engine forward or backward, it is preferred to mount it in the manner shown, and, as illustrated, said bar is secured to one end of a shaft 10, which is mounted in a bracket or standard 11, bolted or otherwise secured to the frame or bed 1. A crank 12 is secured or provided at the opposite end of the shaft 10 and the rod 8 has connection therewith. The reversing-lever 6 is provided with the usual hand-latch for cooperation with a toothed segment for'holding it and the valve-gear in the desired adjusted position.

A box 13 is slidably mounted upon the reversing-bar 5 and is provided with an offstanding stud or stub-shaft 14, upon which rods or, bars 15 and 16 are pivotally mounted. The direction of travelor reciprocating movement of the slide or box 13 is governed by the relative inclination of the reversing-bar 5. Hence when the upper end of the reversing-bar is thrown forward or toward the engine the latter runs in a forward direction, but when the upper end of the bar 5 inclines rearward the engine is driven in a reverse direction. This slide or box 13 has connection with the valve and the means for imparting reciprocating movement to said valve by means presently to be described.

A rod or bar 17 has pivotal connection at one end with the engine or frame, as shown at 18, and its opposite end is connected with the rod or bar 16 through the medium of a stub-shaft 19, projected laterally from a slide or box 20, mounted upon the pitman 3. This slide or box 20 is substantially the same in construction as the part 13, and each is provided with adjustable plates or set-screws therefor to take upwear between them and the parts 3 and 5, upon which the said boxes are slidably mounted. The box 20 moves in a curvilinear path, having the rod or bar 17 as a radius and the part 18 as a center or axis. The pitman 3 passes through the box 20 and at the same time imparts an up-and-down movement thereto corresponding with the oscillation of the said pitman about its connection with the cross-head 4 as an axis. The up-and-down movement of the box is transmitted to the box or slide 13 by means of the rod or bar 16, and through the instrumentality of the connections hereinafter to be described assists materially in operating the valve. The portion of the pitman 3 operating in the box 20 is of uniform cross-sectional area, so as to maintain a close fit between it and the said box.

A lever 21 is fulcrumednear one end to the frame or bed of the engine, and its short arm is pivotally connected with the lower end of a floating lever 22, the upperend of which is pivotally connected with the rod or bar 15. A rod or bar 23 is pivotally attached to the floating lever 22 intermediate of its ends and has pivotal connection with the valve-stem 24E. The long arm of the lever 21 has slidable connection with a box 25, pivotally connected with the cross-head 4, so as to oscillate. As

.the cross-head 4 travels back and forth in coincidence with the piston the box 25 move therewith and is at the same time oscillated by reason of its sliding connection with the lever 21. The reciprocating movement of the cross-head oscillates the lever 2 l, and this oscillatory movement is transmitted to the floating lever 22 and from it to the valve through the connection 23 and stem 24. The reciprocating movement of the connection 23 resulting from the oscillation of the lever 21 fected by the reversing-lever 6 in a manner well understood.

Having thus described the invention,what is claimed as new is' 1. In valve-gear, a rocking reversing-bar, means for reversing the position of said bar, a slide mounted on the bar, a slide mounted upon the pitman, afloating lever, a second lever connected with the floating lever, a box having a sliding connection with the second lever, and pivoted connection with the crosshead, a rod or bar pivotally connecting the JAM box or slide mounted uponthe pitman with the slide on the reversing-bar, a rod or bar pivotally connecting said slide on the reversing-bar with the floating lever, and a connection between the floating lever and the valve, substantially as described.

2. In valve-gear, a rocking reversing-bar, a slide mounted thereon, means for changing the position of the bar, a second slide mounted on the pitman, and having. a pivotal connection with the engine-frame, a box having a pivotal connection with the cross-head, a floating lever, a second lever having a pivotal connection with one end of the floating lever and a sliding connection with said box, a rod or bar pivotally connecting the opposite end of the floating lever with the slide on the reversing-bar, a second rod or bar pivotally connecting the slide on the reversing-bar and pitman, and a rod pivotally connecting the valve and intermediate portion of the lever, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

JOHN A. PIERCE. LL. 8.]

WVitnesses:

T. POLK JAMES, WM. A. WHITAKER. 

